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sept. 16, 1969 United States Patent O 3,466,778 SIGNS William R. Varnelland Mance R. Mitchell, San Antonio, Tex., assignors to ConcreteDevelopment Corporation, San Antonio, Tex., a corporation of Texas FiledFeb. 1, 1965` Ser. No. 429,385 Int. Cl. G09f 7/16, 7/00 U.S. Cl. 40--1362 Claims ABSTRACT OF THE DISCLOSURE An integrally formed concrete signand sign context is made from polyester concrete by mixing polyesterresin with aggregate in the amount of about 40% to about 95% aggregateof the total mixture by weight. The mixture is placed in a mold to forma body having a major plane with a plurality of laterally spacedopenings extending entirely through the body in a direction transverseto the major plane of the body, and the mixture is allowed to cure.

This invention relates to signs made with polyester resin and methodsfor making such signs.

The manufacture of conventional signs, particularly those used outdoors,is an expensive process requiring the selection of a suitable substummaterial upon which the sign is superimposed by painting, photographictechniques, and a variety of other expensive processes. Outdoor signspresently in use are usually made of wood or metal, and must be treatedto prevent weathering, plus the subsequent conventional sign paintingprocesses with coating materials which generally have inferiorweathering characteristics. Such signs are not only expensive tomanufacture, but they are expensive to maintain.

This invention overcomes the disadvantages of conventional signs by theuse of polyester resin. In one form, a sign includes a body having amessage surface with sign characteristics on the message surface of thebody. A coating of polyester resin is disposed over the sign, body, andcharacters to protect them from weathering.

In one specific embodiment, the message surface of the sign body iscovered with a rst coating of polyester resin which may be colored byconventional pigment materials to provide a desired background color.The sign characters are painted or formed on the message surface of thebody using polyester resin which carries pigment of a contrasting color.The polyester resin not only provides a permanent sign background andsign characters, but it also protects the sign body from weathering.Since polyester resin is virtually immune to weathering attack, the signbody and the message on it have an almost indelinite life.

In another form of the invention, the sign body is coated with polyesterresin, and lsign characters formed of polyester resin cement concreteare bonded to the surface of the sign with polyester resin cement. Theterms polyester resin, polyester resin cement, and polyester resincement concrete are defined below.

In the presently preferred embodiment of the invention, the sign is madeof a body having a message Surface and cast from polyester concretewhich includes graded agice gregate present in the amount of about 40%to about 95% of the product by weight. The particle size of theaggregate ranges from less than 400 mesh up through a size limited toabout one-half the thickness of the concrete, and usually from aboutone-eighth inch to about threeeighths inch sieve size. The use of thecarefully graded aggregate provides a lightweight polyester resinconcrete of unusually high strength, plus the additional advantage ofinertness to weathering. Signs made of this material weigh substantiallyless than those made from metal, and have the same physicalcharacteristics such as tensile and comprehensive strength. A sign madefrom polyester concrete costs about 40% less than one made of metal andweighs about 50% less.

In one form, background color is dispersed throughout the messagesurface of the body, and sign characters are applied to the messagesurface either in the form of polyester concrete characters of a colorcontrasting with that of the background color, or polyester cementcharacters applied with a coating which carries pigment of a colorcontrasting with that in the message surface of the sign body. In eitherarrangement, the entire sign is polyester resin cement, or concrete, andis inert to weathering.

Preferably, the aggregate includes fines selected from the groupconsisting of titanium dioxide and silica flour in the amount of about1% to about 50% of the product 'by weight. These lines are virtuallyfree of any metal content, and therefore improve the shelf or pot lifeof the polyester resin cement or concrete. The fine aggregate alsoimproves the strength of the final product, as well as enhancing itsbonding characteristics.

In terms of method, the invention includes the steps of casting a bodywith a message surface from polyester concrete, allowing the mixture toset, and bonding sign characters onto the surface of the message bodywith polyester cement.

In one method of the invention, the sign characters are placed face downin the bottom of a mold for the sign. The polyester concrete mixture ispoured into the mold and onto the characters and allowed to set so thatthe characters are bonded to the set concrete. The strength of the signis further increased by applying pressure to the mixture of polyesterconcrete in the mold until the mixture has set.

These and other aspects of the invention will be more fully understoodfrom the following detailed description and the accompanying drawings,in which:

FIG. 1 is an elevation in cross section of a polyester concrete signbeing cast in a mold with the sign characters integral with the signbody;

FIG. 2 is an elevation of a polyester concrete sign having holes throughit to reduce its weight and wind-loading;

FIG. 3 is a view taken on line 3 3 of FIG. 2;

FIG. 4 is an elevation in cross section of a pressure mold forming apolyester concrete sign with the sign characters being cast directlyinto the sign body;

FIG. 5 is an elevation of a sign made of conventional substrate andcoated with polyester cement, sign characters in the form of polyestercement coating being applied to the coating on the substrate; and

FIG. 6 is a View taken on line 6 6 of FIG. 5.

The term polyester resin is used to mean a mixture of an ethylenicallyunsaturated alkyd resin and polymerizable vinyl monomer such as styrene.The preferred resins of this class for employment in the concretecompositions of the invention are the polymeric ester reaction productsof one or more dicarboxylic acids and one or more polyhydric alcohols.One or more of these reactants contain a reactive double bond orethylenic linkage. Among the dicarboxylic acids which may be used arephthalic, malic, maleic, fumaric, adipic, pimelic, suberic, sebacic,itaconic, citraconic, and succinic acids and their anhydrides. It ispreferred that some of the dicarboxylic acid component of the polyesterresin contain an unsaturated ethylenic linkage. For this reason, maleicand fumarie acids are most desirable. Among the polyhydric alcoholswhich may be used are ethylene glycol, diethylene glycol and propyleneglycol. A mixture of propylene glycol and dipropylene glycol is asatisfactory polyhydric alcohol. An unsaturated monohydric alcohol maybe used in place of part of the polyhydric alcohol. A typical example ofsuch an alcohol is allyl alcohol which produces an allyl ester of thedicarboxylic acid. The polyester resins may be suitably modified orplasticized by the incorporation of alcohols, fatty acids, etc., tomodify the chemical and physical characteristics as desired. Thepolyesters should comprise upward from about or 30% and preferably 40%to 85% by weight of the resin and resin forming component, c g.,styrene, of the coating composition.

The resin should also contain a non-Volatile, monomeric, .cross-linkingsolvent for the polyester. The function of this solvent is to make thepolyester resin more iluid and also to cross-link the polyester at thetime of curing to produce a cross-linked, or three dimensional resinwith the polyester which is thermosetting in character. This monomericsolvent is an important member of the resin component, for it providesthe necessary fluidity to the resin component, imparts thermosettingcharacteristics to the cured resin and is consumed during the curing ofthe resin without forming volatile materials. This freedom fromvolatility is important, for otherwise the release of volatile matterwould produce bubbles, voids, or pinholes on the surface and throughoutthe finished body of the product. The lack of volatile matter permitscuring when under pressure without requiring provision for vents, etc.,in the molds.

Among the monomeric polymerizable solvents which may be used arestyrene, vinyl toluene, e.g., o-vinyl toluene, p-vinyl toluene, andm-vinyl toluene, cyclo-pentadiene; vinyl acetate; diallyl esters, e.g.,diallyl phthalate and triallyl cyanurate, as well as alphamethylstyrene. Styrene has produced the most satisfactory results thus far.

When produced commercially, these resin compositions contain a smallamount of a polymerization inhibitor so as to prevent gelation duringstorage prior to usage. Such inhibitors include the well knownantioxidants: hydroquinone, t-butyl .catechoL quinone, etc.

Some of the polyester resins of the character contemplated for use inthe present invention are sold in the trade and identified as Oronite,Polylite, Selectron, ParapleX, or Vibrin resins. In general, theseresins are unsaturated high molecular weight polymers made by reactingone or more acids or a blend of acids, such as maleic or fumaric acid,with a dihydroxy alcohol, such as ethylene glycol. The speciiicproperties of these resins vary depending largely upon the type andamount of each constituent in the combination.

As the catalysts, there can be utilized numerous oxidizing catalysts,such as cumene hydroperoxide, dicumyl peroxide, benzolyl peroxide, andmethyl-ethyl-ketone peroxide. The catalyst is usually employed in anamount of 0.5-4% of the polyester resin. Preferably, there is utilizedwith the catalyst a metallic dryer such as manganese or cobaltnaphthenate, for example. A typical example of a satisfactorycatalyst-dryer combination is 2% benzolyl peroxide, .75% manganesenaphthenate, and .75 cobalt naphthenate based on the polyester resin.

4 The term polyester cement is used to mean a mixture of polyester resinand between 1% and 50% agggregate having a particle size of less than400 mesh. A typical polyester cement composition is given below:

Example 1 A polyester resin slurry was prepared by stirring in a mixingvessel a mixture having the following composition:

Percent y Weight About 60% by Weight of Oronite CR 21728 polyester resin(made by reacting 3 mols of isophathalic anhydride with 6 mols ofdiethylene glycol and 1. 5 mols of ethylene glycol, until the acidnumber is less than 5. Four mols of maleic anhydride is then added withppm. hydroquinone and reacted until the acid number is below 20), andabout 40% by weight of styrene monomer 69. 20

(The amount of styrene can be increased to about 60% by weight withoutadverse eiect on the nal product. The

Oronite CR 21728 is a so-called semilexible high impact resistanceresin. Similar properties are obtained by blending an orthophathlicrigid resin with an orthophthalic flexible resin in a ratio of about 3.0to 3.9 by Weight.)

(Preferably the silica flour has the chemical and screen analysis givenin Table I below.)

Titanium dioxide Styrene The above materials are thoroughly mixed, andthe mixture is referred to as polyester resin cement mix No. 1. It has adensity of 10.5 pounds per gallon.

The above mixture has yan almost indefinite shelf life because of thepresence of the finely divided and pure silica flour. It can be used asa primer or seal coat in patching conventional portland cementstructures, or it can be mixed with aggregate and cast -as concrete.

Polyester resin cement mix No. 1 is used as the cementing agent of aconcrete designed to meet strength specifications for polyester concretesigns. For example, a polyester concrete is made by mixing the followingingredients:

Example 2 Pounds Polyster resin cement mix No. 1 9.10Methyl-ethyl-ketone peroxide 0.13

(This is preferably blended with the polyester resin Formula No. 1 priorto mixing with the larger aggregate.)

Additional silica our 15.17 Fine (No. 4 to No. 100) silica aggregate134.10 Medium 0%. to No. 4) silica aggregate1 41.50

The aggregate and polyester resin cement mix No. 1 are mixed in astandard concrete mixer for two or three minutes to disperse the variousparticle sizes uniformly throughout the entire mixture and to insureuniform coating of all -aggregate particles with polyester resin.

The above concrete mixture was then cast and cured to make a polyesterconcrete having a compressive strength of 10,000 p.s.i., and a tensilestrength of 2,500 p.s.i. The above concrete may be cured at ambienttemperature. If delay between mixing and placing polyester resinconcrete is expected, the initial set may be delayed from 15 to 30minutes to from 6 to 8 hours by introducing a conventional retarder,such as hydroquinone, in the polyester resin Formula No. 1 when thecatalyst is added.

1(G rade in accordance with New York Port Authority gradation ofaggregate schedule, see Table 1I below.)

The composition of the preferred silica flour is shown in Table I below:

The aggregate used in addition to the silica flour can be any materialwhich does not adversely affect the curing of the polyester resin.Excellent results are obtained by using silica aggregate graded inaccordance with the New York Port Authority Schedule shown in thefollowing table:

TABLE II Percent passing by weight Fine Coarse 1% Coarse Sieve Size(square openings) aggregate aggregate aggregate 1 Used for thinsections. 2 Used for heavy sections.

The polyester resin concrete of Example 2 is satisfactory for use attemperatures up to about 80 C. (176 F.)

To make a polyester concrete for use at temperatures up to 130 C. (266F.), Oronite CR 20114 polyester resin is substituted for Oronite CR21728 in Examples 1 and 2. Other chemical and physical propertiesdescribed above are not `materially changed. Oronite CR 20114 is anisophthalic unsaturated polyester made by reacting one mol ofisophthalic anhydride with 3.41 ymols of propylene glycol at 400 F.until the acid number is below 5. Two mols of maleic anhydride are-added to the mixture, which is then cooked at 390 F. until the acidnumber is below 25. The temperature is then raised to 415 F. until theacid number is below 15. 150 p.p.m. of hydroquinone is added with themaleic anhydride.

Referring to FIG. 1, a body of polyester concrete is cast in a mold 11to form a sign having a message surface 12 adjacent the bottom of themold which is recessed at 13 to form sign characters 14 of polyesterconcrete cast integrally with the sign body on its message surface. Thesign characters project away from the message surface so that they maybe distinguished even though they are the same material as the body ofthe sign. However, preferably the sign characters carry reflectivematerial, such as glass bea'ds, or an inert pigment of distinctive colorwhich causes the sign characters to be more easily distinguished fromthe sign body. In one form, the recesses in the molds in which the signcharacters are formed yare filled with glass beads or pigment ofdistinctive color. The polyester resin concrete is then poured into themold Without disturbing the glass beads or pigment. After the concretehas set, the sign is removed from the mold with the message surfacebeing appropriately covered With the desired message.

Alternatively, the recesses 13 in the mold are filled with glass beadsor pigment with a distinctive color and then with polyester concrete.The floor or bottom of the mold is then covered with pigment of acontrasting color, and then the remainder of the polyester concrete ispoured in place and allowed to set. The nal product is a sign with amessage surface of one background color carrying sign characters ofcontrasting colors or appearance. The iinished product is light weight,yet strong and inert to weathering.

The sign shown in FIGS. 2 and 3 includes a relatively flat rectangularbody 16 made of polyester concrete. The body includes a continuousborder or periphery 1S which encloses a grid type of background made upof a plurality of intersecting diagonal strips 20 upon which polyesterconcrete Vsign characters 22 are bonded with polyester cement. Holes 23between adjacent strips extend through the major plane of the sign body.Reinforcing rods 24 of aluminum, steel, or other suitable material maybe employed, or chopped glass rovings approximately one-half inch inlength may be incorporated into the polyester concrete mixture in anamount not exceeding 60% by weight of the resin content of the polyesterconcrete mixture. An aluminum reinforcing or post-tensioning band 26 isdisposed around the periphery of the sign body and held in tension by aclamp 28 to provide additional strength to the sign. The open grid typeof background of the sign shown in FIGS. 2 and 3 reduces the weight ofthe sign, its cost, and also allows air to pass through the structureand thereby decrease wind-loading requirements. This saving is furtherenhanced because the sign standard or support for the sign can bedesigned for reduced windloading.

Referring to FIG. 4, sign characters 30 are set face down in the bottomof a mold 32 and covered with polyester concrete 34 which is placedunder pressure by a piston 36 to a pressure of 1500 to 3000 pounds persquare inch. The polyester concrete sets in a strong dense body with thesign characters embedded in its message surface. After the concrete isset, the sign is removed from the mold and is ready for installation. Ifdesired, the message surface of the sign is coated with a clear layer ofpolyester resin or cement to protect the sign characters if they are ofmaterial subject to weathering. Of course, this is not necessary if thesign characters are made of polyester concrete because a iilm ofpolyester resin cement covers the aggregate, beads, or pigment whichform the sign characters.

Referring to FIGS. 5 and 6, a conventional sign substrate 40 is coveredwith a coating 41 of polyester resin cement, such as that given inExample 3 below. Sign characters 42 which may be conventional, or whichare made of polyester concrete are bonded with polyester resin cement tothe message surface 43 of the sign substrate. If the sign characters areof polyester concrete, they need uo further protection. If they are of aconventional material subject to weathering, they preferably are coveredwith a coating having the composition given in Example 3 below. Thepolyester coatings can be applied generally with conventional methodsand equipment. Their application does not differ appreciably fromapplying conventional coatings and paints. However, there is oneimportant advantage of the polyester coatings. They donot usuallyrequire prime coats, thus avoiding the multi-coat applications normallyrequired in conventional coating systems. Thus, labor costs are reducedmaterially when polyester coatings are used because they can be appliedin any desired thickness in a one-coat application.

A good polyester resin cement coating for protecting signs in accordancewith this invention is given in the following example:

Example 3 A polyester resin cement coating com-position was prepared bystirring in a mixing vessel a mixture having the following composition:

EXAMPLE 3 Percent Y weight Oronite CR 19583 in about the amount ol'(Made by reacting 1 mol of isophthalic acid and 2.1 mols of propyleneglycol until the acid number is less than 5, at which point 1 mol ofmaleic anhydride is added and the reaction continued until the acidnumber iS below 15, after which about 40% by weight oi styrene monomeris added. The desired acid number is between 10 and 15. The amount ofstyrene can be increased to about 60% by weight without adverse effecton the final product.)

Hydroquinone (approximately 150 p.p.m.) Wax (paran in nature, having amelting poin 125 F. and about 135 F.) Cobalt naphthenate Aluminumsilicate (Al2SO3) Titanium dioxide (TiOZ) Silica dioxide (SiO 2)(Preferable the silica flour has the chemical and screen analysis givenin Table I above.)

Styrene (alpha) 10.50

The above mixture was combined with 1.5 fluid ounces ofmethyl-ethyl-ketone peroxide per gallon of coating composition, and 14grams or 12 cc. hydroquinone.

The pot life of the above mixture was determined and found to be about 6to 8 hours at 80 F. This mixture was applied to a plain steel surface,after Sandblasting to commercial blast-clean specification by spraymethod at approximately to 25 mils lm thickness. The mixture was curedinto a tough corrosion-resistant, semiflexible film within about 24hours at 80 F. The coating of this formulation is particularly suitablein acid environment. The heat distortion point of the resin mixture isabout 80 C Signs using polyester resin cement or concrete in accordancewith this invention have many desirable characteristics not obtainedwith conventional signs. The polyester coatings cure to form a toughcorrosion-resistant, abrasiveresistant film which has superiorweathering characteristics because it provides an almost perfectmoisture vapor barrier. The signs using polyester concrete arelightweight, have high strength, and are virtually inert to weather.

We claim:

1. A method for making an integrally formed concrete sign background andsign context from a polyester concrete comprising mixing polyester resinwith an aggregate in the amount of about 40% to about 95% of the totalmixture by Weight, the aggregate being graded in particle size andranging from less than 400 mesh up through a size commonly limited toabout 1/2 the thickness of the concrete being cast and usually to about1A; inch to 3A; inch sieve size, placing preformed sign contextcharacters on the face of a mold for the product,

placing the sign background mixture into the mold and on the charactersto form a body having a major plane, forming a plurality of laterallyspaced openings extending entirely through the body in a directiontransverse to the major plane of the body, and allowing the polyestermixture to set or cure.

2. A method for making an integrally formed concrete sign background andsign context from a polyester concrete comprising mixing of polyesterresin with an aggregate, in the amount of about 40% to about 95 of thetotal mixture by weight, the aggregate being graded in particle size andranging from less than 400 mesh up through a size commonly limited toabout 1/2 the thickness of the concrete being cast and usually to about1A; inch to 3A; inch sieve size, placing preformed sign contextcharacters on the face of a mold for the product, placing the signbackground mixture into the mold and on the characters to form a bodyhaving a major plane, forming a plurality of laterally spaced openingsextending entirely through the body in a direction transverse to themajor plane of the body, applying pressure to the mixture in the mold,and allowing the polyester mixture to set or cure.

References Cited UNITED STATES PATENTS 1,953,784 4/1934 Straussner etal. 40-136 2,298,364 10/1942 Gits et al 40-136 2,354,857 8/1944 Gits etal 40-l36 2,863,241 12/1958 Gits 40-136 2,994,925 8/ 1961 Gits 40-136LAWRENCE CHARLES, Primary Examiner

